We will try to identify and characterize the molecular interactions between the phage and bacterial components in the various stages of attachment and in the passage of DNA from phage T4 into the cell. Our method for retaining antigen-antibody complexes on glass fiber filters will be utilized for gene purification and recombination studies in T4 and for clinical diagnosis of Serum Lupus Erythematosus and Serum Hepatitis. By utilizing A. aerogenes as host for T4 transformation we hope to develop an assay for small oligodeoxynucleotide fragments.